The United Kingdom (UK) is no longer part of the European Union (EU). The new relationship between the two parties has led to a trade and cooperation agreement (TCA). While the agreement contains some specific tax provisions and ensures the freedom of movement, in principle, it has no direct effect. This raises questions about the actual impact of this agreement for taxpayers. The authors discuss the direct and indirect effect of the agreement, concluding that courts may, in accordance with World Trade Organization (WTO) law, still be held to interpret their domestic (tax) laws in compliance with the principles from the agreement, including comparably formulated fundamental freedoms.